include/linux/ratelimit.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_RATELIMIT_H
   3 #define _LINUX_RATELIMIT_H
   4
   5 #include <linux/param.h>
   6 #include <linux/sched.h>
   7 #include <linux/spinlock.h>
   8
   9 #define DEFAULT_RATELIMIT_INTERVAL      (5 * HZ)
  10 #define DEFAULT_RATELIMIT_BURST         10
  11
  12 /* issue num suppressed message on exit */
  13 #define RATELIMIT_MSG_ON_RELEASE        BIT(0)
  14
  15 struct ratelimit_state {
  16         raw_spinlock_t  lock;           /* protect the state */
  17
  18         int             interval;
  19         int             burst;
  20         int             printed;
  21         int             missed;
  22         unsigned long   begin;
  23         unsigned long   flags;
  24 };
  25
  26 #define RATELIMIT_STATE_INIT_FLAGS(name, interval_init, burst_init, flags_init) { \
  27                 .lock           = __RAW_SPIN_LOCK_UNLOCKED(name.lock),            \
  28                 .interval       = interval_init,                                  \
  29                 .burst          = burst_init,                                     \
  30                 .flags          = flags_init,                                     \
  31         }
  32
  33 #define RATELIMIT_STATE_INIT(name, interval_init, burst_init) \
  34         RATELIMIT_STATE_INIT_FLAGS(name, interval_init, burst_init, 0)
  35
  36 #define RATELIMIT_STATE_INIT_DISABLED                                   \
  37         RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)
  38
  39 #define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)         \
  40                                                                         \
  41         struct ratelimit_state name =                                   \
  42                 RATELIMIT_STATE_INIT(name, interval_init, burst_init)   \
  43
  44 static inline void ratelimit_state_init(struct ratelimit_state *rs,
  45                                         int interval, int burst)
  46 {
  47         memset(rs, 0, sizeof(*rs));
  48
  49         raw_spin_lock_init(&rs->lock);
  50         rs->interval    = interval;
  51         rs->burst       = burst;
  52 }
  53
  54 static inline void ratelimit_default_init(struct ratelimit_state *rs)
  55 {
  56         return ratelimit_state_init(rs, DEFAULT_RATELIMIT_INTERVAL,
  57                                         DEFAULT_RATELIMIT_BURST);
  58 }
  59
  60 static inline void ratelimit_state_exit(struct ratelimit_state *rs)
  61 {
  62         if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE))
  63                 return;
  64
  65         if (rs->missed) {
  66                 pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
  67                         current->comm, rs->missed);
  68                 rs->missed = 0;
  69         }
  70 }
  71
  72 static inline void
  73 ratelimit_set_flags(struct ratelimit_state *rs, unsigned long flags)
  74 {
  75         rs->flags = flags;
  76 }
  77
  78 extern struct ratelimit_state printk_ratelimit_state;
  79
  80 extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
  81 #define __ratelimit(state) ___ratelimit(state, __func__)
  82
  83 #ifdef CONFIG_PRINTK
  84
  85 #define WARN_ON_RATELIMIT(condition, state)     ({              \
  86         bool __rtn_cond = !!(condition);                        \
  87         WARN_ON(__rtn_cond && __ratelimit(state));              \
  88         __rtn_cond;                                             \
  89 })
  90
  91 #define WARN_RATELIMIT(condition, format, ...)                  \
  92 ({                                                              \
  93         static DEFINE_RATELIMIT_STATE(_rs,                      \
  94                                       DEFAULT_RATELIMIT_INTERVAL,       \
  95                                       DEFAULT_RATELIMIT_BURST); \
  96         int rtn = !!(condition);                                \
  97                                                                 \
  98         if (unlikely(rtn && __ratelimit(&_rs)))                 \
  99                 WARN(rtn, format, ##__VA_ARGS__);               \
 100                                                                 \
 101         rtn;                                                    \
 102 })
 103
 104 #else
 105
 106 #define WARN_ON_RATELIMIT(condition, state)                     \
 107         WARN_ON(condition)
 108
 109 #define WARN_RATELIMIT(condition, format, ...)                  \
 110 ({                                                              \
 111         int rtn = WARN(condition, format, ##__VA_ARGS__);       \
 112         rtn;                                                    \
 113 })
 114
 115 #endif
 116
 117 #endif /* _LINUX_RATELIMIT_H */